In the apparatus for supplying starting-fuel for a film or diaphragm type carburetor provided with a bistarter, as disclosed in Japanese Utility Model Publication No. 47(1972)-26744 and Japanese Patent Application Laid-Open No. 60(1985)-204951, the operation of the bistarter and the operation of starting the engine have to be performed independently and simultaneously, and therefore their operation is cumbersome. Further, the starting fuel supplying apparatus is so large in size that the apparatus is difficult to be employed for a portable operating machine which has a limited space for the engine to be mounted.